Automated systems exist for collecting data from meters that measure usage of resources, such as gas, water and electricity. Such systems may employ a number of different infrastructures for collecting this meter data from the meters. For example, some automated systems obtain data from the meters using a fixed wireless network that includes, for example, a central node in communication with a number of endpoint nodes (e.g., meter reading devices (MRDs) connected to meters). At the endpoint nodes, the wireless communications circuitry may be incorporated into the meters themselves, such that each endpoint node in the wireless network comprises a meter connected to an MRD that has wireless communication circuitry that enables the MRD to transmit the meter data of the meter to which it is connected. The endpoint nodes may either transmit their meter data directly to the central node, or indirectly though one or more intermediate bi-directional nodes which serve as repeaters for the meter data of the transmitting node. Some networks operating in this manner are referred to as “mesh” networks.
One type of infrastructure, known in the art as Advanced Metering Infrastructure (AMI), uses two-way communications between collectors and single phase (SP) metering nodes and polyphase (PP) metering nodes to enable collection of metering data, such as kilowatt-hour (kWh), demand, interval, and time-of-use (TOU) data, as well as to enable control actions, such as disconnect, load management, or thermostat control. An AMI system typically consists of meter points connected to a collector via a local area network (LAN). The collector, in turn, is connected to a central head end system via a wide area network (WAN). Because these systems are typically deployed throughout a distribution grid at each point of service, it is desirable that such systems be economical for very large scale deployments.
At various points in an AMI system, the connections between the LAN and the WAN or between the WAN and a stand-alone node are known as “take-out” points because, though one of these take-out points, one can “take out” the data and bring it back to a Head End Server or other system. These take-out points are often implemented using an option board that is installed in a meter or other node. The option board has a connection to a WAN via, for example, a general packet radio service (GPRS) modem, an IEEE 802.11 (b) (“WiFi”) wireless connection, or a public switched telephone network (PSTN) modem.
Typical electrical distribution systems for distributing electrical power to consumers include distribution primary equipment, such as, for example, breakers, capacity banks, transformers, switches, and reclosers. Such systems also typically include dedicated protection and control devices, such as, for example, protective relays or other electronic devices, capacitor bank controllers, load tap changer controllers or voltage regulator controllers, switch controllers, and recloser controllers. It is desirable to have the distribution primary equipment as well as the protection and control devices connected to a high speed Supervisory Control and Data Acquisition (SCADA) System to enable real-time monitoring and control of the power grid. Unfortunately, the costs associated with installing a high speed communication network with connection to the control devices at each piece of primary equipment are prohibitive.
However, if the WAN connection could be shared between the take-out point and nearby Distribution Automation (DA) equipment, both the cost and the complexity of supplying WAN connections to the DA equipment could be reduced. To share the WAN connection, one could implement the system take-out point's WAN communication module as a gateway device in which the incoming WAN communications are intelligently routed by a multi-protocol implementation on the option board. That is, the option board could be configured to receive and generate data packets formatted according to multiple communication protocols. This approach, however, has a number of inherent drawbacks. For instance, implementing multiple protocols and routing functions on a single option board adds to the complexity of the option board, and therefore to the cost. In addition, if the SCADA protocol ever needs to be changed or updated, the option board must also be updated or replaced to ensure continued compatibility with the updated SCADA protocol. Moreover, the additional burden of understanding multiple protocols may require a more powerful microprocessor, more memory, or both. Such upgrades translate directly into higher costs.
Thus, there is a need in the art for a simple and cost-efficient approach to sharing a WAN connection between a take-out point and DA equipment.